1. Field of the Invention
This invention relates to improvements in adjustable ramp apparatus and more particularly, but not by way of limitation, to a hydraulically actuated combination ramp, dock and loader apparatus.
2. Description of the Prior Art
In the loading of vehicles at a warehouse dock, or the like, it is common practice to position the vehicle in the proximity of the dock or ramp area for facilitating the loading of materials onto the vehicle from the storehouse, or conversely for facilitating the unloading of materials from the vehicle for transport to a storage area within the warehouse, or the like. The elevation or height of the bed of the transporting vehicle is frequently at a different elevation than that of the dock, and this may cause a problem in the loading or unloading of the vehicle. In addition, many storehouses, or the like, are multiple storied structures, and it is frequently desirable to transfer the materials from the vehicle to the upper story or second floor of the warehouse, or conversely, it may be necessary to transfer materials from the second floor of the vehicle. In addition, it is frequently desirable or necessary to position the vehicle at an angular orientation with respect to the dock, which increases the difficulty of loading or unloading materials therefrom. The disadvantages of these problems will be readily apparent.
There have been some attempts to solve these problems, such as those shown in the Black U.S. Pat. No. 3,578,185, issued May 11, 1971, and entitled "Mechanized Vehicle System;" and the Royce U.S. Pat. No. 4,155,468, issued May 22, 1979, and entitled "Vehicle Mounted Access Ramp Assembly for Wheel Chair Users." The Black patent relates to a vehicle having a cab section movable ninety degrees to the left of the longitudinal center of the vehicle, and a longitudinally movable bed for the vehicle whereby the cab may be swung aside and the vehicle bed may be moved onto the loading dock. The Royce patent is directed toward a ramp structure for vehicles, the ramp being pivotally mounted for movement between a raised position whereby the ramp becomes a sidewall of the vehicle, and a lowered position whereby the ramp facilitates the entry of a wheel chair from a sidewalk, or the like, into the interior of the vehicle. The Angelo et al U.S. Pat. No. 4,348,780, issued Sept. 14, 1982, and entitled "Apparatus for Elevating a Mobile Rig" is also pertinent in that it relates to a support apparatus for a vehicle, the support apparatus including a pivotal ramp portion which is movable between an angularly disposed position with respect to the ground in order that the vehicle may drive upwardly therefrom. When the vehicle has been positioned on the ramp, one section thereof may be pivoted to an elevated substantially horizontal position for supporting the vehicle in a horizontal position which is elevated with respect to the surface of the ground. These devices have not adequately solved the problems encountered in the loading and unloading of a vehicle, or the like, at a dock area.